Method of manufacturing optical member, and light emitting device

Abstract

A method of manufacturing an optical member includes: providing a polycrystalline wavelength conversion member including phosphor particles and having a first surface and a second surface opposite to the first surface; forming a modified portion inside the wavelength conversion member by focusing laser light inside the wavelength conversion member; and cleaving the wavelength conversion member with the modified portion being a starting point, which includes pressing the wavelength conversion member from a first surface side.

What is claimed is: 
     
         1 . A method of manufacturing an optical member, the method comprising:
 providing a polycrystalline wavelength conversion member comprising phosphor particles and having a first surface and a second surface opposite to the first surface;   forming a modified portion inside the wavelength conversion member by focusing laser light inside the wavelength conversion member; and   cleaving the wavelength conversion member with the modified portion being a starting point, which comprises pressing the wavelength conversion member from a first surface side.   
     
     
         2 . The method of manufacturing the optical member according to  claim 1 , wherein, in the step of cleaving the wavelength conversion member, a support member is disposed on the second surface of the wavelength conversion member, and the wavelength conversion member is pressed from the first surface side by a pressing member. 
     
     
         3 . The method of manufacturing the optical member according to  claim 2 , wherein, in the step of cleaving the wavelength conversion member, the support member is elastically deformed by the pressing of the wavelength conversion member. 
     
     
         4 . The method of manufacturing the optical member according to  claim 1 , wherein, in the step of forming the modified portion, the modified portion is formed at a position spaced apart from the first surface and the second surface. 
     
     
         5 . The method of manufacturing the optical member according to  claim 1 , wherein, in the step of forming the modified portion, the modified portion is formed in a region having a depth of greater than 0 and 10 μm or less from the second surface of the wavelength conversion member. 
     
     
         6 . The method of manufacturing the optical member according to  claim 1 , wherein a length of the modified portion in a depth direction of the wavelength conversion member is 2% or more and 30% or less of a thickness of the wavelength conversion member. 
     
     
         7 . The method of manufacturing the optical member according to  claim 1 , wherein a width of the modified portion in a direction parallel to the second surface of the wavelength conversion member is 1 μm or more and 10 μm or less. 
     
     
         8 . The method of manufacturing the optical member according to  claim 1 , wherein:
 in the step of forming the modified portion, the modified portion is formed in a linear shape in a top view, and   in the step of cleaving the wavelength conversion member, the wavelength conversion member is pressed along the linear-shaped modified portion.   
     
     
         9 . A light emitting device comprising:
 a light emitting element;   an optical member disposed over the light emitting element and having a plate shape; and   a covering member covering lateral surfaces of the optical member and lateral surfaces of the light emitting element, wherein:   an upper surface of the optical member is exposed from the covering member,   the optical member is a polycrystalline wavelength conversion member comprising phosphor particles,   the optical member includes:
 a first region where surfaces of phosphor particles are exposed and 
 a second region where cross sections of phosphor particles are exposed, and 
   the first region and the second region are located at different positions on a lateral surface of the wavelength conversion member in a height direction thereof.   
     
     
         10 . The light emitting device according to  claim 9 , wherein a surface roughness of the first region is greater than a surface roughness of the second region. 
     
     
         11 . The light emitting device according to  claim 10 , wherein
 an arithmetic average surface roughness Ra of the first region is 2.0 μm or more and 3.0 μm or less, and   an arithmetic average surface roughness Ra of the second region is 0.5 μm or more and 1.0 μm or less.   
     
     
         12 . The light emitting device according to  claim 9 , wherein the first region is provided over all of the lateral surfaces of the optical member along outer edges of a lower surface of the optical member.